JP2000344706A - Production of acetaldehyde - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce acetaldehyde from methyl acetate, carbon monoxide and hydrogen in high yield and selectivity over a long period. SOLUTION: Acetaldehyde is produced from methyl acetate, carbon monoxide and hydrogen by vapor-phase catalytic reaction. The reaction is carried out in the presence of a catalyst containing rhodium and palladium under a pressure of >6 MPa and <=10 MPa to activate the catalyst when the catalytic activity is lowered and <=6 MPa otherwise.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing acetaldehyde by reacting methyl acetate with carbon monoxide and hydrogen in a gas phase.

[0002]

2. Description of the Related Art Acetaldehyde is conventionally produced by the Wacker oxidation of ethylene with oxygen, and there are two methods, a one-step method and a two-step method, using a water-soluble catalyst system of palladium chloride, copper chloride and hydrochloric acid. Has been put to practical use. In the Wacker method, a high chloride ion concentration and a large amount of copper chloride are required, so that the apparatus is highly corrosive, and it is necessary to use a material such as titanium which is practically expensive. Further, since chlorine-based by-products are generated, it is necessary to appropriately separate and dispose of the by-products, and there is a problem of cost. Under the influence of raw material circumstances, as a method not using ethylene, (1) a method of reacting acetic anhydride and hydrogen at normal temperature, normal pressure and in liquid phase using a platinum oxide catalyst or a metal palladium catalyst supported on barium sulfate ( Chem. Ber., 95, 1844 (1962)), (2) A method of producing from acetic anhydride and synthesis gas using a cobalt carbonyl catalyst (Japanese Patent Publication No. 48-19285), (3) Using a rhodium chloride catalyst. And hydrogenation of acetic anhydride at 100 to 200 ° C. under liquid phase pressure in the presence of triphenylphosphine (US Pat. No. 3,579,566). In the case of these methods, industrialization is considered difficult because the yield and selectivity of acetaldehyde are very low.
(4) In a synthesis method from methyl acetate, carbon monoxide and hydrogen using a catalyst supporting a rhodium compound and a palladium compound (Japanese Patent Publication No. 63-37092), the reaction rate of methyl acetate is about 5%, The selectivity is about 88% and the yield of acetaldehyde is low.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for producing acetaldehyde by contacting methyl acetate, carbon monoxide and hydrogen in the gas phase while keeping the catalyst highly active. .

[0004]

Means for Solving the Problems The present inventors have prepared a catalyst comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound, or rhodium and / or a palladium compound.
Or a catalyst comprising a rhodium compound and palladium and / or a palladium compound and an alkali metal halide and / or an alkaline earth metal halide, methyl acetate,
When producing acetaldehyde by gas-phase catalytic reaction from carbon monoxide and hydrogen, if the activity of the catalyst is reduced, by reacting at a pressure higher than normal for a certain period of time, it is possible to perform the reaction by returning to normal pressure. They have found that acetaldehyde can be obtained in high yield, and have reached the present invention.

That is, the present invention relates to a method for producing acetaldehyde from methyl acetate, carbon monoxide and hydrogen, comprising a method comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound. Alternatively, in the presence of a catalyst to which an alkaline earth metal halide is further added, the catalyst is activated by reacting at a pressure of more than 6 MPa and not more than 10 MPa only when the catalyst activity is reduced,
The present invention relates to a method for producing acetaldehyde which reacts at a pressure of MPa or less.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The acetaldehyde synthesis catalyst used in the present invention is a catalyst comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound, or a rhodium and / or rhodium compound and a palladium and / or a palladium compound and a halogen. It is a catalyst comprising an alkali metal halide and / or an alkaline earth metal halide, and the catalyst may be further treated with an organic halogen compound.

Specific examples of the rhodium compound used as a raw material of the catalyst of the present invention include rhodium trichloride, rhodium hexamine chloride, rhodium ammonium hexachloride, rhodium acetate, and rhodium nitrate. Ammonium palladium chloride,
Palladium acetate, dichlorotetramine palladium, palladium nitrate and the like can be mentioned. Preferred as alkali metal halides and alkaline earth metal halides are alkali metal halides such as lithium, sodium and potassium and alkali earth metal halides such as magnesium, calcium and strontium.
These may be used alone or in combination of two or more.

Rhodium, rhodium compound, palladium,
The palladium compound, alkali metal halide and alkaline earth metal halide are usually supported on a carrier. Examples of the carrier include activated carbon, alumina, silica, silica-alumina, zirconia, titania and the like. Preferably, activated carbon or zirconia can be used.
The amount of rhodium, rhodium compound, palladium, palladium compound, alkali metal halide or alkaline earth metal halide supported on the carrier is 0.1 to 10 as a metal.
wt%, preferably 0.5 to 5 wt%. Rhodium and / or
Alternatively, the ratio between the rhodium compound and palladium and / or the palladium compound and the alkali metal halide or the alkaline earth metal halide may be any value, and can be freely adjusted within this range. The method of supporting rhodium, a rhodium compound, palladium, a palladium compound, an alkali metal halide and an alkaline earth metal halide on a carrier is carried out by a generally known method, for example, by impregnation.

Rhodium, a rhodium compound, palladium, a palladium compound, an alkali metal halide and an alkaline earth metal halide supported on a carrier may be treated with an organic halogen compound. Preferred as organic halogen compounds are methyl iodide, methyl bromide, acetyl iodide, acetyl bromide, and the like, with iodide being particularly preferred. The organic halogen compounds may be used alone or in combination of two or more. The method of treating with an organic halogen compound may be any method, and the catalyst may be brought into contact with an organic halogen compound or a solution containing the organic halogen compound. When the organic halogen compound is used by dissolving it in a solvent, the solvent is preferably one that does not adversely affect the catalyst and the reaction, and is preferably methanol, ethanol, acetone, or toluene. Specifically, before charging the catalyst, it may be contacted by a batch method,
After the filling, the treatment may be carried out by supplying and contacting the organic halogen compound-containing solution to the catalyst by a continuous method instead of the raw materials. The amount of the organic halogen compound used in the treatment of the catalyst is 0.5 to 5 times, preferably 1 to 5 times the weight of the catalyst.
It is twice. The temperature of the organic halogen compound treatment may be room temperature or higher, and the pressure may be normal pressure or higher.

When the treatment with an organic halogen compound is carried out by a batch method, the above-mentioned amount of the organic halogen compound is added to the catalyst, brought into contact with the catalyst, air-dried, and then filled with the catalyst. The contact time is at least 1 minute, preferably at least 5 minutes. In addition, in the case of performing the continuous method, the above amount of the organic halogen compound may be added to and brought into contact with the catalyst. At this time, a gas may be entrained, and the gas may be a carbon monoxide / hydrogen mixed gas used for the reaction, nitrogen,
An inert gas such as helium or argon may be used. The amount of entrained gas may be about the same as during the reaction, and is 1000 to 3000 h ^{-1 in} GHSV.
Is fine. The supply of the organic halogen compound may be carried out in 10 minutes or more, preferably in 0.5 to 2 hours. Before the reaction or treatment with an organic halogen compound, heat treatment may be performed under a stream of an inert gas such as nitrogen, helium, or argon, or reduction may be performed at 100 to 400 ° C. under a stream of carbon monoxide or hydrogen. Is also good.

Using the above acetaldehyde synthesis catalyst,
When producing acetaldehyde by reacting methyl acetate with carbon monoxide and hydrogen in gas phase, usually 6 MPa or less,
The reaction is preferably performed at a pressure of 2 MPa or more and 6 MPa or less. Only when the activity of the catalyst is low or when the activity of the catalyst is reduced, without stopping the reaction, only the pressure condition of the various reaction conditions is set to a value greater than 6 MPa and 10 MPa.
The catalyst is activated by reacting at the following pressures for a certain period of time, and then returned to a normal pressure. Thus, the activity of the catalyst is improved by performing the reaction treatment for a certain period of time under the condition of the normal operating pressure or higher. The reaction time is 0.1 to 24 hours, preferably 1 to 8 hours. The reaction treatment with the high pressure may be performed before the catalyst is filled in the reactor, immediately after the catalyst is charged in the reactor, or after the reaction has been performed for a certain time. Alternatively, the reaction under normal pressure and the reaction under high pressure of the present invention may be repeated. When producing acetaldehyde using the method of the present invention, a cocatalyst is required. Halogen compounds used as cocatalysts are iodides, chlorides, bromides and the like, for example, methyl iodide, methyl bromide, acetyl iodide, acetyl bromide and the like. These may be used alone or in combination of two or more. In the reaction of the present invention, methyl acetate, a co-catalyst, hydrogen, and carbon monoxide may be allowed to flow, and the reaction may be performed on the above catalyst. At this time, the reaction can be performed even in the presence of an inert gas such as nitrogen. The ratio of hydrogen to carbon monoxide is
The molar ratio (hydrogen / carbon monoxide) is 0.1 to 10, preferably 0.1.
25-4. The gas volume is less than 5000h ^-1 in GHSV,
The reaction is preferably carried out at 1000 to 3000 h ^-1 . The raw material methyl acetate and the co-catalyst halogen compound may be supplied individually or as a mixture. The ratio of the halogen compound in the supply amount (methyl acetate + cocatalyst) is 10 to 50 wt.
%, Preferably 20 to 40% by weight. WHSV as supply
At 10 h ^-1 or less, preferably 5 h ^-1 or less.
The reaction temperature should be higher than the temperature at which the supplied methyl acetate or cocatalyst is vaporized, and is generally 100 to 300 ° C, preferably
Perform the reaction at 150-250 ° C. Next, the method of the present invention will be described more specifically with reference to Examples and Comparative Examples. However, the scope of the present invention is not limited by these examples.

[0012]

EXAMPLES Comparative Example 1 Granular activated carbon (Kuraray Chemical Co., Kuraray Coal GC, 10-
32 mesh) is immersed in an aqueous hydrochloric acid solution of palladium chloride and rhodium chloride trihydrate, and the granular activated carbon is separated and dried by an evaporator. A catalyst impregnated and supported on granular activated carbon was prepared. This catalyst was heat-treated at 400 ° C. for 3 hours under a nitrogen stream, and then charged into a zirconium reactor. 2mm diameter above and below the catalyst
The catalyst was fixed by filling a porcelain Raschig ring of φ, height 2 mm. In the reaction, 4 MPa, 200 ° C., a hydrogen / carbon monoxide mixed gas (50/50 mol%) was supplied to the reactor at a rate of GHSV = 3000 h ⁻¹ , and a methyl acetate / methyl iodide mixed solution (80/20 wt.
%), And then supplied to the reactor at a rate of WHSV = 2 h ^-1 . The gas after the reaction was cooled, and the obtained product liquid and generated gas were analyzed by gas chromatography. As a result, acetaldehyde and acetic acid were obtained as main components. The reaction results are as follows. In the reaction results, selectivity refers to the percentage of the moles of each product to the moles of methyl acetate utilized. Conversion rate of raw material methyl acetate is 13%. Selectivity for acetaldehyde 86% Selectivity for paraaldehyde (trimer of acetaldehyde)
5% Selectivity for acetic acid 103% Selectivity for methane 0.7% Selectivity for ethylidene diacetate 0%

Example 1 After the reaction of Comparative Example 1, the reaction pressure was increased from 4.0 MPa to 6.5 MPa, and a hydrogen / carbon monoxide mixed gas (50/5
0 mol%) is supplied to the reactor at a rate of GHSV = 3000 h ^{−1, and} a mixed solution of methyl acetate / methyl iodide (80/20 wt%) is vaporized and then supplied at a rate of WHSV = 2 h ⁻¹ , Reaction treatment was performed. Thereafter, the reaction was carried out at 4 MPa under the same conditions as in Comparative Example 1. As a result, the conversion of the raw material methyl acetate was improved, and acetaldehyde and acetic acid were obtained as main components. The reaction results are as follows. Conversion rate of raw material methyl acetate 29% Selectivity of acetaldehyde 77% Selectivity of paraaldehyde (trimer of acetaldehyde) 8% Selectivity of acetic acid 111% Selectivity of methane 1% Selectivity of ethylidene diacetate 0.5%

Comparative Example 2 Granular activated carbon (Kuraray Chemical Co., Kuraray Coal GC, 10-
32 mesh) palladium chloride, rhodium chloride trihydrate
And immersed in an aqueous solution of lithium chloride and hydrochloric acid.
Separated charcoal, dried by evaporator, and 1
wt% palladium chloride equivalent, 1wt% rhodium chloride equivalent
Trihydrate and 0.5% lithium chloride equivalent to granular activated carbon
An impregnated supported catalyst was prepared. Put this catalyst under a stream of nitrogen
 After heat treatment at 400 ℃ for 3 hours, it is made of zirconium
The reactor was charged. Above and below the catalyst, diameter 2mmφ, height
A 2 mm porcelain Raschig ring was filled to fix the catalyst.
The reaction is performed at 4MPa, 200 ℃, hydrogen / carbon monoxide mixed gas (50
/ 50mol%) GHSV = 3000h ^-1To the reactor at the rate of
A mixture of methyl acetate / methyl iodide (80 / 20wt%)
WHSV = 4h^-1To the reactor at a rate of
Was performed. After the reaction, the gas is cooled and the resulting product liquid
And product gas are analyzed by gas chromatography.
Was. As a result, acetaldehyde and acetic acid are the main components
I got it. The reaction results are as follows. Conversion rate of raw material methyl acetate 15% Selectivity of acetaldehyde 95% Selectivity of paraaldehyde (trimer of acetaldehyde)
 0% Selectivity for acetic acid 100% Selectivity for methane 1% Selectivity for ethylidene diacetate 1%

Example 2 After the reaction of Comparative Example 2, the reaction pressure was increased from 4.0 MPa to 6.5 MPa, and the mixed gas of hydrogen / carbon monoxide (50/5) was heated at 200 ° C. for 6 hours.
0 mol%) is supplied to the reactor at a rate of GHSV = 3000 h ^{−1, and} a mixed solution of methyl acetate / methyl iodide (80/20 wt%) is vaporized and then supplied at a rate of WHSV = 4 h ⁻¹ , Reaction treatment was performed. Thereafter, the reaction was carried out at 4 MPa under the same conditions as in Comparative Example 2. As a result, the conversion of the raw material methyl acetate was improved, and acetaldehyde and acetic acid were obtained as main components. The reaction results are as follows. Conversion rate of raw material methyl acetate 20% Selectivity of acetaldehyde 96% Selectivity of paraaldehyde (trimer of acetaldehyde) 0% Selectivity of acetic acid 100% Selectivity of methane 1% Selectivity of ethylidene diacetate 1%

[0016]

According to the production method of the present invention, acetaldehyde can be produced from methyl acetate, carbon monoxide and hydrogen in a high yield and a high selectivity for a long period of time.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) // C07B 61/00 300 C07B 61/00 300 F term (reference) 4G069 AA03 AA08 BA08B BB02A BB02B BC01A BC01B BC04A BC04B BC08A BC71A BC71B BC72A BC72B CB19 CB51 DA05 EA01X EA01Y FA08 4H006 AA02 AC29 AC45 BA02 BA06 BA10 BA24 BA25 BA30 BA32 BA34 BA37 BA41 BA55 BA71 BC10 BC11 BC32 BE20 BE40 BQ10 4H039 CA62 CL45

Claims (4)

[Claims] 1. A method for producing acetaldehyde from methyl acetate, carbon monoxide and hydrogen by a gas phase catalytic reaction, comprising a catalyst comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound, or rhodium and / or rhodium. In the presence of a catalyst comprising a compound and palladium and / or a palladium compound and an alkali metal halide and / or an alkaline earth metal halide, react at a pressure of more than 6 MPa and not more than 10 MPa only when the catalytic activity is reduced. Characterized in that the catalyst is activated by the method described above, and the other components are reacted at a pressure of 6 MPa or less. 2. A method for producing acetaldehyde from methyl acetate, carbon monoxide and hydrogen by a gas phase contact reaction, wherein the composition comprises rhodium and / or a rhodium compound and palladium and / or a palladium compound, or rhodium and / or Rhodium compound and palladium and / or
Or a palladium compound and an alkali metal halide and / or
Or, when the catalytic activity is reduced in the presence of a catalyst obtained by treating a composition comprising an alkaline earth metal halide with an organic halogen compound, the composition is larger than 6 MPa and 10
A method for producing acetaldehyde, comprising activating a catalyst by reacting at a pressure of not more than MPa and reacting at a pressure of not more than 6 MPa otherwise. 3. A catalyst comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound.
Alternatively, the reaction pressure is set to 6 MPa in the presence of an acetaldehyde synthesis catalyst comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound and an alkali metal halide and / or an alkaline earth metal halide.
The activation of the acetaldehyde synthesis catalyst, characterized in that the acetaldehyde synthesis catalyst is simultaneously activated while producing acetaldehyde from methyl acetate, carbon monoxide, and hydrogen by gas phase contact reaction by making the pressure larger than 10 MPa or less. Method. 4. A composition comprising rhodium and / or a rhodium compound and palladium and / or a palladium compound, or a rhodium and / or rhodium compound and palladium and / or a palladium compound and an alkali metal halide and / or an alkaline earth halide. Reaction pressure of more than 6 MPa and 10 MPa in the presence of a catalyst obtained by treating a composition composed of a class of metals with an organic halogen compound
A method for activating an acetaldehyde synthesis catalyst, which comprises simultaneously producing acetaldehyde from methyl acetate, carbon monoxide, and hydrogen by gas phase contact reaction while simultaneously activating the acetaldehyde synthesis catalyst.